Project Summary/Abstract: In response to the national public health crisis of opioid misuse and addiction, the National Institute of Health (NIH) launched the HEAL (Helping to End Addiction Long-term) Initiative in April 2018 to aggressively drive the development of scientific tools that will end the opioid crisis by accelerating effective discoveries through the FDA for drug approval. The HEAL Initiative development programs over the next five years are expected to result in 15 Investigational New Drugs (INDs) applications and at least 5 New Drug Applications (NDAs). The NIH HEAL Initiative has issued this RFA-DA-19-002 under the National Institute on Drug Abuse (NIDA) to ?support the discovery and development of medications to prevent and treat opioid use disorders (OUD) and overdose.? INSYS Development Company, Inc. (INSYS) has developed cannabidiol oral solution, which shows promise as a novel medication for prevention of relapse that addresses one of the five opportunities specified to improve treatment options (Opportunity 4). INSYS, in collaboration with KAI Research, Inc., plans to initiate the clinical develop program of Cannabidiol Effects on Craving and Relapse Prevention in Opioid Use Disorder consisting of three proposed clinical trials under the UG3/UH3 Phases: 1. For the UG3 phase, INSYS in collaboration with principal investigator Edythe London, PhD (UCLA) will conduct a randomized, double-blind, placebo controlled, dose-ranging study of cannabidiol oral solution on cue-induced cravings, modulation of withdrawal, alteration in negative affect states, relapse to opioid use, and treatment retention in patients with OUD receiving buprenorphine treatment in a residential drug treatment facility. The findings from this study will be used to support the transition to the UH3 phase. 2. For the UH3 phase, INSYS in collaboration with principal investigator Kathleen Brady, MD, PhD (MUSC) will conduct two studies in an outpatient setting: ? A randomized, double-blind, placebo-controlled, parallel-group study of cannabidiol oral capsule as adjunctive therapy to buprenorphine naloxone for treatment in patients with opioid use disorder. ? A randomized, double-blind, active-controlled, parallel-group, double-dummy, proof-of- concept study of cannabidiol oral capsule compared to naltrexone as monotherapy for treatment in patients with opioid use disorder.